Somatostatin, or somatotropin-release inhibitory factor (SRIF), is a cyclic peptide found in humans. It is produced widely in the human body and acts both systemically and locally to inhibit the secretion of various hormones, growth factors and neurotransmitters. The effects of somatostatin are mediated by a family of G protein-coupled receptors, of which five subtypes are known. These subtypes are divided into two subfamilies, the first comprising SSTR2, SSTR3 and SSTR5 and the second SSTR1 and SSTR4.
Somatostatin is involved in the regulation of processes such as for example cellular proliferation, glucose homeostasis, inflammation and pain.
In this aspect somatostatin or other members of the somatostatin peptide family are believed to inhibit nociceptive and inflammatory processes via the SSTR4 pathway.
A number of further therapeutic areas for SSTR4 agonists have been discussed (see e.g. Crider, A; Mini Rev. Med. Chem. 2002, 7, 213 (and references therein); WO 2010/059922 (and references therein).
Selective SSTR4 agonists have been disclosed, for instance, in J. Am. Chem. Soc. 1998, 120, 1368-1373.
WO 2010/059922 provides pyrrolidine carboxamide agonists of SSTR4.
However, there is further need for selective SSTR4 agonists, especially for non-peptidic agonists, which show high stability and other advantageous properties, such as oral efficacy and metabolic stability.
Substituted 3-azabicyclo[3.1.0]hexane derivatives have been discussed for the use as inhibitors of the glycine type-1 transporter (WO 2005/037216), for the use as CCR2 (chemokine receptor 2) antagonists (WO 2012/125661) or for the treatment of renal injuries and hypertension (CN 102675290).
Aim of the Invention
It has now been found that compounds of the present invention according to general formula (I) are effective agonists of somatostatin receptor 4 (SSTR4).
Besides the agonistic property toward somatostatin receptor 4, the compounds of the present invention provide advantageous pharmacokinetic properties. For example the compounds of the present invention show high metabolic stability.
Furthermore, the compounds according to the present invention show high selectivity for the SSTR4 receptor with respect to the other subtypes of the same subfamily including the SSTR1 receptor. As a consequence the probability of side effects is reduced.
Accordingly, one aspect of the invention refers to compounds according to formula (I) and salts, hydrates or solvates thereof as agonists of somatostatin receptor 4.
Another aspect of the invention refers to compounds according to formula (I) and salts, hydrates or solvates thereof as selective agonists of SSTR4 over other subtypes of the same family, including selectivity over the other subtype of the same subfamily (SSTR1).
A further aspect of the invention relates to the physiologically acceptable salts of the compounds of general formula (I) according to this invention with inorganic or organic acids.
In a further aspect this invention relates to pharmaceutical compositions, containing at least one compound according to formula (I) or a physiologically acceptable salt, hydrate or solvate thereof, optionally together with one or more inert carriers and/or diluents.
A further aspect of the present invention relates to compounds according to formula (I) or a physiologically acceptable salt thereof or pharmaceutical compositions comprising compounds according to formula (I) or physiologically acceptable salts thereof for the use in the prevention and/or treatment of disorders related to SSTR4.
Another aspect of the invention relates to processes of manufacture of the compounds of the present invention.
A further aspect of the present invention relates to compounds according to formula (I) or a physiologically acceptable salt thereof or pharmaceutical compositions comprising compounds according to formula (I) or physiologically acceptable salts thereof for the use in the prevention and/or treatment of diseases or conditions which can be influenced by activation of SSTR4. In this aspect the present invention relates to compounds according to formula (I) or a physiologically acceptable salt thereof for the treatment of pain of various origins and/or inflammation.
Other aims of the present invention will become apparent to the skilled man directly from the foregoing and following remarks.